by Yamiche Alcindor and Melanie Eversley, USA TODAY

by Yamiche Alcindor and Melanie Eversley, USA TODAY

BOSTON - President Obama found himself at an all too familiar event Thursday; a somber ceremony where he tried to comfort victims of a deadly tragedy.

"Everyone of us has been touched by the attack on your beloved city,'' Obama said, speaking at an interfaith service dedicated to the three people killed and 176 injured in twin bombings at Monday's Boston Marathon.

"For millions of us, what happened in Boston Monday is personal,'' he said at the Cathedral of the Holy Cross as part of a 90-minute service that included comments by clergy, Boston Mayor Thomas Merino and Massachusetts Gov. Deval Patrick.

Speaking to those who lost limbs or were severely injured at the marathon's finish line, Obama vowed "you will run again."

He issued a warning to those responsible for the attacks. "They picked the wrong city to do this,'' Obama said. "Yes we will find you. And yes, you will face justice,'' he said, later calling their acts "small and senseless."

Obama's appearance here in the wake of another tragedy had a familiar tone that was part comfort, part support and part rallying cry for victims and the nation. It was a tone similar to that when he spoke following the 2009 serial shooting at Fort Hood, Texas; the 2011 shooting in Tucson that killed six people and wounded 13, including Rep. Gabrielle Giffords; the 2012 shooting at a suburban Denver movie theater that left 12 dead; and the December shooting at Sandy Hook Elementary School, in which 20 children and six staff members were killed.

Jocelyn Perez was smiling as she left the service in a wheelchair. Jocelyn, 10, who lives outside Boston, was watching the marathon Monday with her mother and other family members when the blasts hit.

Perez's mother, Sara Valverde Perez, remains in intensive care. Her mother's sister and Jocelyn's aunt, Tania Valverde, said the service was comforting because it included a speech by Roberto Miranda, pastor from the family's church.

Jocelyn, who suffered cuts from the blast is doing as well as can be expected, Valverde said. "Physically, yes -- emotionally, not so much," she said as the family boarded a shuttle back to Boston's Beth Israel Hospital.

Mary Jo Brogna, a registered nurse based at Beth Israel Hospital who was on duty when the blasts shook the marathon, said the president's message was badly needed.

"I've been a nurse 31 years and I've never seen anything so horrific," said Brogna, 52, of Quincy, Mass., her expression distant. Of Obama's speech, she said, "I think it was inspirational. I think it's going to bring people together."

Speaking ahead of the president, Mayor Merino praised firefighters, medical personnel and Bostonians for reacting swiftly to attend to victims. "This was the strength of our city at work,'' he said. "Nothing will take us down, because we take care of each other."

Groups of people had come in waves to the church, surrounded by volunteers dressed in bright yellow Boston Marathon jackets. A woman began openly sobbing as she neared the entrance. Hospital staffers and volunteers from the American Red Cross quickly surrounded her, embracing her and helping her walk.

Anne Thibau, who was injured in the leg and back from Monday's blasts, wore a T-shirt reading "I Love Boston" as she prepared to enter the cathedral. She wasn't hoping for any particular message from the president, but simply wanted to be in a place of comfort. "I thank God that I walked away" from the blasts, said Thibau, 57.

Boston resident Sharon Butler-Charles was among a swarm of people who'd gotten to the cathedral early Thursday, but not early enough to get a ticket inside.

"I was born and raised in Dorchester, and I really felt for the little fellow that was killed (Martin Richard, 8, Dorchester)," said Butler-Charles, 50. "I just wanted to give support."

Dozens of people gathered in the gymnasium of Cathedral High School to watch the service. Security to get inside was tight as police searched purses and confiscated items like apples, which one officer warned could be thrown. Anyone entering had to pass through a metal detector. There was silence as the service began and people stared intently at the images of speakers whose voices echoed through the room.

Ann Sanfilippo of Gloucester, Mass. was among those watching the service at the high school.. She said Obama delivered the right message. "It was uplifting and very much what we needed right now. He was very comforting and I felt like he gave me hope. He reminded me when I wake up tomorrow, the sun will rise."

People lined up early hoping to get into the church service. One of them, Regina Fisher, 57, got in line at 11 p.m. Wednesday and stood outside all night.

"I haven't slept a wink and I probably won't sleep when I get home," she said. "I came because I care about people and it hurts me when innocent souls get hurt."

Bostonian Amanda Ayers was volunteering at the marathon's mile 18 water station when the explosions hit. She doesn't know anyone who was killed or hurt. But Thursday morning, Ayers, 27, got to the line to get into the church just as general admissions tickets were being passed out at 7 a.m.

Watching Obama on television didn't feel personal enough, said Ayers, a student at Boston University.

"Being here, with other people makes it real," she said. "This happened in our city. I want to be with my Boston people."